Blue-green light photochromism in europium doped BaMgSiO4

BaMgSiO 4 (BMS) can be sensed to blue light (wavelength λ=405 nm) by doped europium (Eu). Eu doped BMS turns to bright pink, and is bleached by green light (λ=475–532 nm) irradiation in several seconds. The coloration-decoloration process is repeatable and first. The colored state hardly changes for over 480 h (20 days), and is stable even at 100 °C. The blue-green light photochromism can be explained by electron transfers between doped Eu and oxygen defects. The doped Eu broadens the absorption band of BMS, and supplies excited electrons. The oxygen defects form electron traps, which catch excited electrons, and become F-like color centers.